Well, it is not often we conduct interviews underwater, but we are about to hear from Fabien Cousteau who was part of a project called Mission 31. He and a team of scientist have been living and conducting research at an underwater base for the past 31 days. They were submerged 63 feet off the Florida Keys and just returned to the surface this morning. Now, if Cousteau's name sounds familiar, there's a reason. It was Fabien's grandfather, Jacques Cousteau who pioneered the idea of living underwater to do research. His famous first mission was 50 years ago, and his grandson was marking that anniversary. We reached Fabien yesterday as he and his team were packing up. I asked him to describe the underwater base.

FABIEN COUSTEAU: The Marine laboratory that we're in right now is about the size of a school bus. And inside it is everything that we need that's contained - so our life-support system, our cameras, our science equipment, dive gear and everything else. It's separated into four sections. The two main sections are the sleeping quarters and the living quarters, and then beyond that, we have a dry lab where we perform a lot of experiments. And then, finally, on the opposite end of where the bunk room is is our wet porch, my favorite part of the habitat because it's our front door to the ocean world. It's on the floor and there are stairs leading into the water. And I love being able to just walk into the ocean.

GREENE: You know, I was reading about what you're doing. Your body pressurizes in a way that, when you're down there for a long period of time, it lets you take much longer dives. Isn't that right?

COUSTEAU: That's the real luxury and benefit of living on the frontier - is being able to be there. My grandfather used to say, in order to film a fish, you have to become a fish. And this is the best way to do it.

GREENE: What's one of the best memories of one of these long dives?

COUSTEAU: Well, I've never seen a goliath grouper strike a barracuda, which we had the unbelievable luck to see right outside this viewport.

GREENE: Is that a violent confrontation?

COUSTEAU: It was quite violent. It was a territorial behavior. There were scales flying and everything else. - other things like being unbelievably lucky to have spotted eagle rays flying around the habitat for the last almost 31 days. I see them as our escorts and guardians throughout the mission. I mean, it's just been a wonderful and magical experience.

GREENE: What - what do these escorts look like?

COUSTEAU: Spotted eagle rays are a medium-sized ray with, as their name implies, spots all over the top of their bodies. They are anywhere from four to six foot wingspan and with a tail that can be as much as eight to 10 feet long.

GREENE: Wow.

COUSTEAU: They have been hanging around here for the entirety of the mission, which is extraordinary unusual.

GREENE: You did a lot of experiments while you were underwater for these 31 days. Is there one that stands out that you think our listeners would sort of learn something from hearing about?

COUSTEAU: As far as the science is concerned, we've been able to leverage a lot of the latest and greatest in technologies to find out more about what's happening to our coral reefs. And this is such an amazing, fabulous fireworks display of life down here, and we barely scratched the surface. And I'm looking out the window right now - Sorry. I got distracted. I see three spotted eagle rays flying right in front of the viewport right now, and it is just an amazing site I will never tire of this, even after 31 days or 31 years. It's just a beautiful sight.